A production installation for block books in parallel has been described in which the block books are digitally printed on basic sheets arranged in sequence along a previously printed strip unwinding from a spool. Each block book has a given number of book sheets, and each basic sheet has a number of book sheets that is identical to the amount of block books to be produced. The basic sheets are constituted by sections of the strip of book sheets arranged in a single row. The printed strip therefore shows a number of columns (four in the disclosed example) equal to the number of block books and a number of sections equal to the number of book sheets of the block books. The installation cuts the strip transversely by separating the various sections, stacks the sections with the basic sheets side by side and, after longitudinal cuts for separating the columns, bonds an edge the block books and proceeds to a serial arrangement for following manufacturing operations.
The installation of the prior art has limitations on the number of block books which can be manufactured in parallel, depending on the width of the strip and problems of reliability in dependence of the low stability of the stacked sheets to the stresses associated to the cuts and the separations.